Effects of charges of Eu 3+ -doped LDH laminates on drug loading capacity and drug release as well as its anticancer effects

In order to investigate the effects of the charges of Eu 3+ -doped layered double hydroxide laminates on the drug loading capacity and drug release, anticancer drug methotrexate was loaded into a series of Eu 3+ -doped MgAl-layered double hydroxides with different layer charges. X-ray diffraction results suggested that the methotrexate was successfully loaded into the interlayer of the Eu 3+ -doped MgAl-layered double hydroxides. Zeta potential test revealed that the positive charges on the laminates of the Eu 3+ -doped MgAl-layered double hydroxides gradually increased when the Mg 2+ /(Al 3+ + Eu 3+ ) molar ratio varied from 3.0, 2.0, 1.5, to 1.3. After the negatively charged methotrexate was loaded into the Eu 3+ -doped MgAl-LDHs, the positive charges of laminates obviously decreased. The loading capacity of the Eu 3+ -doped LDH for methotrexate gradually increased with the increasing positive charges of the laminates. However, the drug release exhibited similar kinetic behavior despite the different charge numbers of laminates. Fluorescent spectra indicated that all the Eu 3+ -doped MgAl-layered double hydroxides showed fluorescent changes during drug delivery and release. In vitro cytotoxicity experiment through CCK-8 assay suggested that the intercalated methotrexate could be successfully controlled-released from drug delivery system and exhibited anticancer effects against HepG2 cancer cells.